A poll believed to be the first to reveal the impact of redundancies on minority and vulnerable groups has found that one in four workers believe they have been disproportionately affected by the recession.

The poll, which surveyed hundreds of workers in London, found a quarter thought that groups including older employees, women and visible ethnic minorities had been particularly targeted by redundancies.

"The fact that employees are recording perceptions of disproportionate redundancies among minority groups is strong evidence of discrimination," said Arpita Dutt, a partner in employment law at Russell Jones & Walker. "In addition their perceptions are unlikely to include 'invisible' victims of discrimination, such as those with mental health problems."

Lawyers are increasingly warning that companies making redundancies are failing to sufficiently take issues of discrimination into account. "There are subtle ways in which employers can discriminate in making redundancies," employment barrister Christina Lyons said. "Disabled employees and pregnant women enjoy a special status during a redundancy exercise, whereas ethnic minorities do not."

The results of the poll have been published to coincide with the implementation of changes to procedures that employers must follow when making redundancies.

The updated grievance, disciplinary and employment tribunal procedures mean employers no longer have to show compliance with statutory procedures to prove that a dismissal was fair. Instead, they will be expected to follow a code of practice in situations where there is a possibility of race discrimination, designed to encourage both employers and employees to resolve workplace grievances and disputes early on and avoid the need for litigation.

Head of employment law at Nabarro, Sue Ashtiany, said: "The change in procedural safeguards are intended to allow greater flexibility between employers and employees resolving disputes in the workplace.

"There is already quite a bit of case law around how employers are supposed to be fair and open and consult with their staff before chopping their jobs."

However, lawyers have warned that the "crowding" of minority employees into certain industries and types of work leaves them vulnerable to discrimination. "Some employers may have a particularly high number of ethnic minorities", said Lyons. "In carrying out a redundancy exercise an employer may be applying a criterion that appears to be neutral, but has an effect that is indirectly discriminatory."

Redundancy procedures are likely to come under continuing scrutiny as unemployment figures reach two million for the first time in 12 years.